Sheet metal cutting device

ABSTRACT

A cutting tool for cutting sheet metal especially sheet metal ducts. The tool has two interconnected pivoted arms, one of said arms is motor driven and has a rotary cutting blade and a circular rotary holding member connected to its outer end. The other arm has another circular holding member on its end positioned so that it bears against the first rotary member when the arms are pivoted together to hold the sheet metal while it is being cut.

United States Patent [191 DeSantis June 11, 1974 SHEET METAL CUTTING DEVICE [76] inventor: Louis DeSantis, 15 Shaker Ridge Ln., Commack, NY. 11725 22 Filed: Nov. 6, 1972 211 App1.No.:304,147

[52] US. Cl 30/124, 30/264, 30/500 [51] Int. Cl B26b 25/00 [58] Field of Search 30/101, 102, 124, 180, 30/187, 240, 263, 264, 276, 103, 108, 265, 500

[56] References Cited UNITED STATES PATENTS 967,456 8/1910 Smith 30/265 X 2,728,985 1/1956 Quackenbush 30/265 2,861,340 11/1958 Hazzard 30/264 Primary Examiner-James L. Jones, Jr. Assistant Examiner-J. C. Peters Attorney, Agent, or Firm-Stephen E. Feldman 5 7 ABSTRACT A cutting tool for cutting sheet metal especially sheet metal ducts. The tool has two interconnected pivoted arms, one of said arms is motor driven and has a rotary cutting blade and a circular rotary holding member connected to its outer end. The other arm has another circular holding member on its end positioned so that it bears against the first rotary member when the arms are pivoted together to hold the sheet metal while it is being cut.

8 Claims, 3 Drawing Figures PATENTEDJun 1 1 I814 FIG SHEET METAL CUTTING DEVICE BACKGROUND OF THE INVENTION This invention relates to cutting tools and especially to a tool for removing metal from ducts, such as air conditioning and heating ducts. When such ducts are installed in abuilding either when the building is under construction or after it has been built, the ducts are installed in a manner so that the vertical extensions of the duct work will lie flush with the ceiling after they are installed so that a register may be placed over the open end of the duct and the register will be level with the ceiling.

In order to make sure that the end of the duct is level with the ceiling the duct is very often made longer that it finally needs be. By making it longer it can be cut back to the properlength so it lies flush with the ceiling. It is extremely difficult if not impossible to predict the exact height of-the ceiling when it is initially installed and thus it is almost impossible to predict the exact length of the finished duct while the duct is being installed. The best procedure is to make the duct longer and then to cut it off to the proper height after it has been installed. At present it is very difficult to accomplish this cutting procedure with conventional cutting devices, such as metal shears and other similar devices, as it is awkward and cumbersome to reach inside the duct to accomplish the cut that is needed. There have been some attempts to provide a mechanized tool to accomplish this result. However, these tools while providing a motarized cutting member have lacked any provisionto hold the metal of the duct that is being cut off. If this metal is not properly held its weight near the end of-the cut will cause the duct to rip off during the cutting operation'leaving a jagged edge. The previous devices also did not have a cutting edge that would ex, tend to a sufficient depth so that a smooth cut could be provided. Therefore it would bedesirable if a motarized cutting tool could be provided which would have SUMMARY OF THE INVENTION A sheet metal cutting tool is provided having two pivoted arms each of which has a circular holding member at its outer end. One of the arms is motor driven and also has a circular cutting blade at its outer end. When the two arms are brought together they hold the metal that is being removed from the duct between them and the circular blade cuts through the duct. The holding members are positioned so that the cut section of the duct will be properly held and the metal will not fall or tear away during the cutting operation.

It is thus an object of this invention to provide a motarized sheet metal cutting tool having provision for properly holding the metal of a duct as it is being cut and also for causing the cutting blade to penetrate completely through the metal for a sufficient distance so as to provide a clean smooth cut.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall view of the cutting tool of this invention.

FIG. 2 is a top view of the holding and cutting section of the tool of FIG. 1.

FIG. 3 shows the tool in operation in a duct.

PREFERRED EMBODIMENT OF THE INVENTION The cutting tool of this invention as shown in FIG. 1, includes a first arm 2 which is a straight steel rod having one end which is flat and adapted to be inserted into a drill chuck. (This will be described in more detail hereinafter.) The other end of this member end 6, has a smaller diameter screw threaded end 8. On this end is fitted a short cylindrical slightly flexible holding member 10 which may be composed of a hard rubber or similar stiff flexible material. This member has a channel 12 through it; The channel has a larger diameter section 14 into whichrod 2 fits and a smaller diameter section 16 into which the threaded members fits. The circular cutting edge is mounted on top of thiscircular member. The cutting edge 18, is made of toughened steel or other similar material and is beveled on both sides throughout its circumference so that it has a V- shaped knife edge. The diameter of this cutting member is greater than the diameter of the circular holding member 10 so that the cutting member extends further from the rod than the circular support member. At the end of the rod a wing nut 20 is provided. The wing nut screws into the circular threaded end of the rod to hold the holding member and cutting edge to the rod. A perpendicular circular projecting member 22 also extends from the rod proximate to the end of the rod 4 that is adapted to fit into a drill chuck. This projection is extremely short and is positioned to interconnect this rod with the other arm of the cutting tool, as will be explained hereinafter.

The other arm of the tool, arm 24 consists of two sections, an upper section 26 and a lower section 28. These two sections are connected by a coupling 30. The upper section consists of a straight part 32 and a bent part 34, the latter being bent at an angle of approximately to the straight part. The other section 28, of this rod also consists of a straight part 36 and another part 38 which is positioned at a 60 angle to part 36. The coupling 30 which connects the two sections of the rod consists of a cylindrical hollow member having an internal circular opening, the diameter of which is slightly less than the diameter of rod 24. However the ends of the internal opening are slightly larger in diameter so that each of the sections 26 and 28 of rod 24 can fit into this opening 40. The connecting member also has another channel 1, perpendicular to channel 40, that is, channel 42 which consists of two slightly tapered openings. Pin 22 which is connected to the other arm fits into this channel so that the two arms can pivot in scissor-like fashion toward and away from each other. Arm 24 has a suitable handle with a hand grip 48 thereon. The hand grip 48 can have finger openings 50 so as to make it easier to hold. The end of the rod ends in a screw thread 52 to connect the rod to the grip.

The other end 26 of the rod 24 has a circular holding member connected thereto. This holding member 52 in a like manner to the other holding member consists of a touch flexible material such as hard rubber or other similar material and has an internal opening 54 in it. The member is placed over rod 24 and then a circular ball bearing race with ball bearings 56 is placed around rod 24 and in this opening 54. On top of that are placed suitable washers 58 and 60 and end plate 62. The end plate is the same diameter as the circular member and is fastened thereto by screws 54 to hold the ball bearings and washers in place. The two holding members 52 and will now contact each other when they are pivoted together.

To limit the insertion of rod 24 into the duct an adjustable limiting member 68 is provided. This consists of a rectangular shaped member having an opening 70 through which rod 24 passes. A suitable wing nut and screw are provided to hold member 68 to rod 24. The wing nut also permits the member 68 to be raised and lowered to the desired position. This will be discussed in more detail hereinafter.

In operation a conventional electric drill such as shown in FIG. 3 or similar motor means is connected to rod 2 by placing the end of the rod in the chuck of the drill. The drill and the hand grip are then separated apart from each other so that the arms and especially the two holding members 52 and 10 are separated in a scissor like manner.

Arm 24 is then inserted into a duct 69 as shown in FIG. 3. The other arm 2 is positioned on the outside of the duct. Arm 2 is placed at the desired height by adjusting limiting member 68 so that it rides on the bottom 74 of the duct 69. This determines where the cut will take place. The motor is then started so that rod 2 begins to rotate. This will cause knife edge 18 to rotate and therefore to cut into the sheet metal to a sufficient depth to cause a smooth even cut. The cutting edge penetrates to a sufficient distance since it is greater in diameter than holding member 10 and therefore will penetrate to a distance that is the difference between its radius and the radius of the holding member 10. This penetration permits the forward edge of the blade as shown by arrow 60 in FIG. 2 to do the cutting. This permits a much smoother cut than if the perpendicular part of the cutting edge 62 were doing the cutting. As the cutting edge is cutting into the duct, holding means 52 and 10 hold the cut section of the duct (76 in FIG. 3) to prevent this cut section from falling. If the holding members did not hold this section it would rip off due to the force of its own weight before it was fully cut off. This would leave an undesirable jagged edge and also might rip away and distort part of the other duct work.

Further, the rotation of rod 2 causes the rotation of holding member 10 so as to drive the cutting tool around the duct. Holding member 52 will follow since it is freelyrotatable on its ball bearings 56. The cutting member will then completely cut through the duct so as to make it even with the ceiling as shown by number 78 in FIG. 3 so that a register or other device can be placed over the duct.

It will be appreciated that the scissor action permits the tool to be readily inserted and removed from the duct.

The start of the cut can take place in any desired fashion, such as by starting at the bottom and swinging up through an arc (As shown in FIG. 3) or simply by starting at the desired height and cutting straight through.

Thus it will be appreciated that a sheet metal cutting tool has been described. The cutting tool provides an efficient motarized way of removing sheet metal from a duct.

While a specific embodiment of the invention has been described it will be appreciated that many modifications therein may be made by ones skilled in the art which falls within the true spirit and scope of the invention.

I claim:

1. A sheet material cutting tool comprising a first arm a circular cutting member positioned at one end thereof a first circular holding member having a smaller diameter than said cutting member and positioned proximal said cutting member said arm being capable of having rotating means attached at the other end to rotate the arm a second arm pivotably connected to said first a second circular holding member positioned at the end of one end of said second arm and positioned in a plane below said cutting member, said member mounted to cooperate with the circular holding member of the first arm to hold material therebetween while it is being cut by the circular cutting member, and

a handle positioned at the other end of said second arm.

2. The sheet material cutting tool of claim 1 wherein said circular cutting member and said circular holding member of said first arm are positioned thereon adjacent one end of said arm and wherein the other end of said first arm is adapted to be connected to a source of motarized power to rotate said arm.

3. The sheet material cutting tool of claim 2 wherein the circular holding member of said second arm is rotatably supported by bearings on said second arm.

4. The sheet material cutting tool of claim 3 wherein the material is sheet metal and wherein the arms are pivotably connected in a scissor configuration.

5. The sheet material cutting tool of claim 4 wherein the cutting member is positioned on said first arm closer to the proximate end of said arm than said holding member.

6. The sheet material cutting tool of claim 5 wherein the second arm has a hand grip at the other end of said arm from said holding member.

7. The sheet material cutting tool of claim 6 wherein the second arm consists of two sections which are connected together by an interconnecting member in which the first arm is pivoted.

8. The sheet material cutting tool of claim 7 wherein the first arm comprises a straight rod and wherein the second arm comprises a curved arm, the first and second sections each being bent in substantially 60 angles so that the rod is substantially S shape in configuration. 

1. A sheet material cutting tool comprising a first arm a circular cutting member positioned at one end thereof a first circular holding member having a smaller diameter than said cutting member and positioned proximal said cutting member said arm being capable of having rotating means attached at the other end to rotate the arm a second arm pivotably connected to said first a second circular holding member positioned at the end of one end of said second arm and positioned in a plane below said cutting member, said member mounted to cooperate with the circular holding member of the first arm to hold material therebetween while it is being cut by the circular cutting member, and a handle positioned at the other end of said second arm.
 2. The sheet material cutting tool of claim 1 wherein sAid circular cutting member and said circular holding member of said first arm are positioned thereon adjacent one end of said arm and wherein the other end of said first arm is adapted to be connected to a source of motarized power to rotate said arm.
 3. The sheet material cutting tool of claim 2 wherein the circular holding member of said second arm is rotatably supported by bearings on said second arm.
 4. The sheet material cutting tool of claim 3 wherein the material is sheet metal and wherein the arms are pivotably connected in a scissor configuration.
 5. The sheet material cutting tool of claim 4 wherein the cutting member is positioned on said first arm closer to the proximate end of said arm than said holding member.
 6. The sheet material cutting tool of claim 5 wherein the second arm has a hand grip at the other end of said arm from said holding member.
 7. The sheet material cutting tool of claim 6 wherein the second arm consists of two sections which are connected together by an interconnecting member in which the first arm is pivoted.
 8. The sheet material cutting tool of claim 7 wherein the first arm comprises a straight rod and wherein the second arm comprises a curved arm, the first and second sections each being bent in substantially 60* angles so that the rod is substantially S shape in configuration. 